 Birds are endothermic animals. That is, they make their body warm with the help of their metabolic heat production. Birds have a specific mode of life, that is, aerial mode of life. For some part of their life, they live in air. That is, they fly in air and then they go back to the maybe land or maybe upon the trees where they make their nest. Birds also have a four-chambered heart. Their heart is comparatively larger and its four chambers are actually fully divided because to continue their flight action, that is, they have to fly. And for flying, they need a lot much of energy and for flying, they need a lot much of oxygen. So their heart is fully divided into four chambers and its size is larger to compensate the needs of the oxygen supply and nutrient supply of the birds. Birds also have a specific character because they have to fly and weight is very important. To reduce weight, they have very lightweight bones, which are hollow, we call them hollow bones. Their very lightweight bones actually help them to reduce weight for flight. They aspire through a very specific system which includes lungs and associated structures called air sacs. Birds have their lungs, which could be of course expanded, which are expanded to a greater extent. Also, they have specific structures associated with their lungs called air sacs. When they get air in, inhale air, it is filled into the air sacs as well and those air sacs also help in its respiration. So its respiration system is highly efficient with the help of lungs and with the help of air sacs. We know that we have parrots, pigeons, peacocks, falcons, kingfishers, birds could be herbivores, birds could be carnivores. They are consumers and they are present at different levels of consumers. There are grain eater birds. We know the sparrows, they are usually grains. There are some birds which eat meat like a kingfisher, which eat upon the fishes. So they make a very important part of the food chain and the food webs. If for example there are certain birds which eat upon the dragonflies, we know that if those birds, they are not present in the environment, then those dragonflies may increase so much that they may eat a lot many crops. So they are very important parts of the food chains and food webs of most of the ecosystems. Birds have another characteristic that they lay fewer eggs and they provide parental care to their young ones. We know that the birds usually make nests and in the nests they lay their eggs and then they take care of their eggs and when their young ones are born, they feed them and they grow them up for a specific period of time till they are self-dependent. So birds, they are very important animals of the animal kingdom and of the very important part of the biosphere. Have a look on different types of birds. They also add to the beauty of the nature. They have very beautiful birds like you can see peacock, you can see different other types of birds here in this picture. Now the mammals. The group which is classified on the top of the vertebrates. The highly complex organisms. Mammals which have hair on their body and which feed their young ones with milk. Mammals also have a fourth chambered heart which is also a double-circuit heart and that is it receives blood from the body which is deoxygenated and it sends blood to the lungs to oxygenate it. They have their respiratory system consist of lungs. They respire through lungs and they are very, very efficient lungs and the heart system because of the cardiorespiratory system. They have highly developed brains in comparison to all the previous groups they have a different property that their brain is highly developed and this highly developed brain actually provides the social interaction between these organisms. That is they are socially involved and they make groups or sort of families in which they provide each other protection, support and shelter and sometimes help each other in feeding as well. The animals, they have a thick skin in comparison to all other organisms and this thick skin actually help them to protect themselves, their bodies from the harsher environment. The mammals, they are also heterotrophs. They are from herbivores to omnivores. There is a wide diversity of mammals present on the planet Earth. There are a lot many mammals like the goats like the buffaloes like the cows which are herbivores and there are a lot many different mammals like the wolves which are carnivores there are different types of mammals which are omnivores like bears white bears, the black bears there is a wide diversity of mammals. These are very useful for us as human beings so we culture them in our farmhouses we culture the buffaloes we culture the cows we culture the goats we use them for the purpose of getting meat which is a good source of proteins and we use them for getting milk and we apply different types of breeding techniques to improve their different characteristics. So and also there are different types of mammals which are very very important parts of the food chains like there are certain arctic foxes there are arctic bears which live in specific environment and which are very very important in the quality of those ecosystems. So this was about the vertebrate animals vertebrate animals from fishes to the mammals they have very very specific characteristics and they are highly adapted for their specific environments and in many ways they are very useful for us in many many ways they are sometimes harmful for us but we but these are always they are harmful whether they are useful they are important for us because if they are harmful we have to handle with them we have to evolve strategies to deal with them and if they are useful we can use them for getting different types of important products for us. So today's lecture was about different types of animals their distinguishing features their different characteristics their economic importance their their benefits and their harms and about their importance for the biosphere.